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Sud A, Parry EM, Wu CJ. The molecular map of CLL and Richter's syndrome. Semin Hematol 2024; 61:73-82. [PMID: 38368146 DOI: 10.1053/j.seminhematol.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/16/2024] [Accepted: 01/20/2024] [Indexed: 02/19/2024]
Abstract
Clonal expansion of B-cells, from the early stages of monoclonal B-cell lymphocytosis through to chronic lymphocytic leukemia (CLL), and then in some cases to Richter's syndrome (RS) provides a comprehensive model of cancer evolution, notable for the marked morphological transformation and distinct clinical phenotypes. High-throughput sequencing of large cohorts of patients and single-cell studies have generated a molecular map of CLL and more recently, of RS, yielding fundamental insights into these diseases and of clonal evolution. A selection of CLL driver genes have been functionally interrogated to yield novel insights into the biology of CLL. Such findings have the potential to impact patient care through risk stratification, treatment selection and drug discovery. However, this molecular map remains incomplete, with extant questions concerning the origin of the B-cell clone, the role of the TME, inter- and intra-compartmental heterogeneity and of therapeutic resistance mechanisms. Through the application of multi-modal single-cell technologies across tissues, disease states and clinical contexts, these questions can now be addressed with the answers holding great promise of generating translatable knowledge to improve patient care.
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Affiliation(s)
- Amit Sud
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA; Harvard Medical School, Boston, MA; Broad Institute of MIT and Harvard, Cambridge, MA; Department of Immuno-Oncology, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Erin M Parry
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA; Harvard Medical School, Boston, MA; Broad Institute of MIT and Harvard, Cambridge, MA.
| | - Catherine J Wu
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA; Harvard Medical School, Boston, MA; Broad Institute of MIT and Harvard, Cambridge, MA; Department of Medicine, Brigham and Women's Hospital, Boston, MA
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Verma SK, Kuyumcu-Martinez MN. RNA binding proteins in cardiovascular development and disease. Curr Top Dev Biol 2024; 156:51-119. [PMID: 38556427 DOI: 10.1016/bs.ctdb.2024.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
Congenital heart disease (CHD) is the most common birth defect affecting>1.35 million newborn babies worldwide. CHD can lead to prenatal, neonatal, postnatal lethality or life-long cardiac complications. RNA binding protein (RBP) mutations or variants are emerging as contributors to CHDs. RBPs are wizards of gene regulation and are major contributors to mRNA and protein landscape. However, not much is known about RBPs in the developing heart and their contributions to CHD. In this chapter, we will discuss our current knowledge about specific RBPs implicated in CHDs. We are in an exciting era to study RBPs using the currently available and highly successful RNA-based therapies and methodologies. Understanding how RBPs shape the developing heart will unveil their contributions to CHD. Identifying their target RNAs in the embryonic heart will ultimately lead to RNA-based treatments for congenital heart disease.
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Affiliation(s)
- Sunil K Verma
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine Charlottesville, VA, United States.
| | - Muge N Kuyumcu-Martinez
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine Charlottesville, VA, United States; Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, United States; University of Virginia Cancer Center, Charlottesville, VA, United States.
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Jowhar Z, Xu A, Venkataramanan S, Dossena F, Hoye ML, Silver DL, Floor SN, Calviello L. A ubiquitous GC content signature underlies multimodal mRNA regulation by DDX3X. Mol Syst Biol 2024; 20:276-290. [PMID: 38273160 PMCID: PMC10912769 DOI: 10.1038/s44320-024-00013-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/21/2023] [Accepted: 01/03/2024] [Indexed: 01/27/2024] Open
Abstract
The road from transcription to protein synthesis is paved with many obstacles, allowing for several modes of post-transcriptional regulation of gene expression. A fundamental player in mRNA biology is DDX3X, an RNA binding protein that canonically regulates mRNA translation. By monitoring dynamics of mRNA abundance and translation following DDX3X depletion, we observe stabilization of translationally suppressed mRNAs. We use interpretable statistical learning models to uncover GC content in the coding sequence as the major feature underlying RNA stabilization. This result corroborates GC content-related mRNA regulation detectable in other studies, including hundreds of ENCODE datasets and recent work focusing on mRNA dynamics in the cell cycle. We provide further evidence for mRNA stabilization by detailed analysis of RNA-seq profiles in hundreds of samples, including a Ddx3x conditional knockout mouse model exhibiting cell cycle and neurogenesis defects. Our study identifies a ubiquitous feature underlying mRNA regulation and highlights the importance of quantifying multiple steps of the gene expression cascade, where RNA abundance and protein production are often uncoupled.
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Affiliation(s)
- Ziad Jowhar
- Department of Cell and Tissue Biology, UCSF, San Francisco, USA
- Medical Scientist Training Program, University of California, San Francisco, San Francisco, CA, 94158, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Albert Xu
- Department of Cell and Tissue Biology, UCSF, San Francisco, USA
- Medical Scientist Training Program, University of California, San Francisco, San Francisco, CA, 94158, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, 94158, USA
| | | | | | - Mariah L Hoye
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, USA
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, USA
- Department of Cell Biology, Duke University Medical Center, Durham, USA
- Duke Regeneration Center, Duke University Medical Center, Durham, USA
- Department of Neurobiology, Duke University Medical Center, Durham, USA
- Duke Institute for Brain Sciences, Duke University Medical Center, Durham, USA
| | - Stephen N Floor
- Department of Cell and Tissue Biology, UCSF, San Francisco, USA.
- Helen Diller Family Comprehensive Cancer Center, San Francisco, USA.
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Park JE, Desai H, Liboy-Lugo J, Gu S, Jowhar Z, Xu A, Floor SN. IGHMBP2 deletion suppresses translation and activates the integrated stress response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.11.571166. [PMID: 38168189 PMCID: PMC10760061 DOI: 10.1101/2023.12.11.571166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
IGHMBP2 is a non-essential, superfamily 1 DNA/RNA helicase that is mutated in patients with rare neuromuscular diseases SMARD1 and CMT2S. IGHMBP2 is implicated in translational and transcriptional regulation via biochemical association with ribosomal proteins, pre-rRNA processing factors, and tRNA-related species. To uncover the cellular consequences of perturbing IGHMBP2, we generated full and partial IGHMBP2 deletion K562 cell lines. Using polysome profiling and a nascent protein synthesis assay, we found that IGHMBP2 deletion modestly reduces global translation. We performed Ribo-seq and RNA-seq and identified diverse gene expression changes due to IGHMBP2 deletion, including ATF4 upregulation. With recent studies showing the ISR can contribute to tRNA metabolism-linked neuropathies, we asked whether perturbing IGHMBP2 promotes ISR activation. We generated ATF4 reporter cell lines and found IGHMBP2 knockout cells demonstrate basal, chronic ISR activation. Our work expands upon the impact of IGHMBP2 in translation and elucidates molecular mechanisms that may link mutant IGHMBP2 to severe clinical phenotypes.
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Affiliation(s)
- Jesslyn E. Park
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, California, USA, 94143
| | - Hetvee Desai
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
| | - José Liboy-Lugo
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, California, USA, 94143
| | - Sohyun Gu
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
| | - Ziad Jowhar
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, California, USA, 94143
| | - Albert Xu
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, California, USA, 94143
| | - Stephen N. Floor
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California, USA, 94143
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Owens MC, Shen H, Yanas A, Mendoza-Figueroa MS, Lavorando E, Wei X, Shweta H, Tang HY, Goldman YE, Liu KF. Mutant forms of DDX3X with diminished catalysis form hollow condensates that exhibit sex-specific regulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.19.533240. [PMID: 38076929 PMCID: PMC10705264 DOI: 10.1101/2023.03.19.533240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Mutations in the RNA helicase DDX3X, implicated in various cancers and neurodevelopmental disorders, often impair RNA unwinding and translation. However, the mechanisms underlying this impairment and the differential interactions of DDX3X mutants with wild-type (WT) X-linked DDX3X and Y-linked homolog DDX3Y remain elusive. This study reveals that specific DDX3X mutants more frequently found in disease form distinct hollow condensates in cells. Using a combined structural, biochemical, and single-molecule microscopy study, we show that reduced ATPase and RNA release activities contribute to condensate formation and the catalytic deficits result from inhibiting the catalytic cycle at multiple steps. Proteomic investigations further demonstrate that these hollow condensates sequester WT DDX3X/DDX3Y and other proteins crucial for diverse signaling pathways. WT DDX3X enhances the dynamics of heterogeneous mutant/WT hollow condensates more effectively than DDX3Y. These findings offer valuable insights into the catalytic defects of specific DDX3X mutants and their differential interactions with wild-type DDX3X and DDX3Y, potentially explaining sex biases in disease.
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Wilkins KC, Schroeder T, Gu S, Revalde JL, Floor SN. Determinants of DDX3X sensitivity uncovered using a helicase activity in translation reporter. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.14.557805. [PMID: 37745530 PMCID: PMC10515938 DOI: 10.1101/2023.09.14.557805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
DDX3X regulates the translation of a subset of human transcripts containing complex 5' untranslated regions (5' UTRs). In this study we developed the helicase activity reporter for translation (HART) which uses DDX3X-sensitive 5' UTRs to measure DDX3X mediated translational activity in cells. To dissect the structural underpinnings of DDX3X dependent translation, we first used SHAPE-MaP to determine the secondary structures present in DDX3X-sensitive 5' UTRs and then employed HART to investigate how their perturbation impacts DDX3X-sensitivity. Additionally, we identified residues 38-44 as potential mediators of DDX3X's interaction with the translational machinery. HART revealed that both DDX3X's association with the ribosome complex as well as its helicase activity are required for its function in promoting the translation of DDX3X-sensitive 5' UTRs. These findings suggest DDX3X plays a crucial role regulating translation through its interaction with the translational machinery during ribosome scanning, and establish the HART reporter as a robust, lentivirally encoded measurement of DDX3X-dependent translation in cells.
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Affiliation(s)
- Kevin C. Wilkins
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, 94143, USA
- Graduate Division, University of California, San Francisco, San Francisco, CA, United States
| | - Till Schroeder
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, 94143, USA
- Julius-Maximilians-University of Würzburg, Würzburg, 97070, Germany
| | - Sohyun Gu
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, 94143, USA
| | - Jezrael L. Revalde
- Department of Pharmaceutical Chemistry, University of California, 600 16th Street, San Francisco, California 94143, United States
| | - Stephen N. Floor
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, 94143, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California, 94143, USA
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